This invention relates to a method and apparatus for feeding a welding wire. Generally when an automatic welding is effected, it is necessary to feed a welding wire to a welding portion of a workpiece. It is necessary to feed an electrode wire in a consumable electrode type automatic arc welding such as a CO.sub.2 gas arc welding, submerged arc welding etc., and an additive wire in a nonconsumable electrode type automatic arc welding such as a TIG arc welding etc. and an automatic electroslag welding, to a welding portion of a workpiece. The welding wire is usually fed toward the workpiece by inserting the wire through a wire guide axial bore of a conduit cable connected at a wire exit end thereof to a welding torch and imparting a wire feed force from a wire supply roll mechanism to the wire at the wire entry end of the conduit cable. In the conventional welding wire feed method, however, the welding wire is fed normally in a spiral state along the inner surface of a wire guide hole of a conduit cable. In this case the welding wire is circular in cross section and has an equal bending rigidity in all directions represented by horizontal and vertical axes passing through an axis thereof, and the conduit cable has a wire guide bore of a circular cross section, the inner diameter of which is sufficiently larger than an outside diameter of the welding wire. The welding wire is subjected during the feeding operation to an end load P.sub.O when it is passed through a welding torch section and a feed force P.sub.F from a wire supply roll mechanism and the wire is buckled in the wire guide bore of the conduit cable, causing it to be spirally curved along the inner surface of the conduit cable. For this reason, the welding wire is slidably moved in a circumferential direction along the inner surface of the wire guide bore of the conduit cable and during the sliding movement of the welding wire a frictional resistance is applied as a wire guide load P.sub.A to the welding wire. As a result, the welding wire is maintained normally in a predetermined, spirally curved state by a force relation between a feed force and a feed load P.sub.O + P.sub.A. The wire guide load P.sub.A is increased with an increasing end load P.sub.O and in proportion to the length of the conduit cable, preventing provision of a low-output, and thus compact, wire feed roll mechanism. Furthermore, a smooth, stable feeding of the welding wire is prevented. In order to alleviate the wire guide load P.sub.A, attempts have been made in the art to make a frictional resistance of the welding wire to the inner surface of the wire guide bore smaller by, for example, applying a lubricant to the inner surface of the wire guide bore of the conduit cable, but with partial success.